Method of insulating high voltages in electrical precipitators



Dec. 20, 1932. HQWES 1,891,645

METHOD OF INSULATING HIGH VOLTAGES IN ELECTRICAL PRECIPITATORS FiledJan. 29. 1930 l ill llihli In vm for Raymond Zlbwfl A Home):

Patented Dec. 20, 1932 UNITED STATES PATENT OFFICE RAYMOND T. HOWES, 01LOS ANGELES, CALIFORNIA, ASSIGNOR 0F ONE-THIRD TO A. A. ANDERSON, OF LOSANGELES, CALIFORNIA, AND (ENE-THIRD TO L. A. SNYDER, OF

WILMINGTON, CALIFORNIA METHOD OF INSULATING HIGH 'VOLTAGES IN ELECTRICALPRECIPITATORS Application filed January 29, 1930. "Serial No. 424,218.

This invention relates to a means and method of insulating electrodes inoil dehydrators and the like.

A method of dehydrating oil has been develo ed which is comprisedessentially of pro ucing an electrical discharge between an electrodeimmersed in oil and the surrounding shell. The voltage employed for thispurpose is usually in a range between 18,000 and 100,000 volts, Whensuch a discharge takes place the minute water particles in t e oilcoalesce and drop out of suspension in the oil. Also other particles offoreign matter are frequentl brou ht down with the water.

Because 0 the iigh voltages employed some difficulty has been present inkeepirg the electrode insulated from the ground shell. In theconventional construction the electrode is extended into the shellthrough the roof thereof and attempts have. been made to provide aninsulating bushin which keeps the electrode insulated from the shell.However, it has been found that in a relatively short time a carbondeposit will take place on the surface of the bushing or there will beother deposits such as water thereon which will form a short circuitbetween the electrode and the shell.

It is an object of this invention to prov de an improved means andmethod of maintaining the electrode insulated from the grounded shelland preventing any deposits forming on the insulating bushing whichenable such short circuiting.

With the fore 0mg and other ob]ects in view, which will e made manifestin the followingdetailed description, and specifically ointed out in theappended claims, reference 15 had to the accompanying drawing for anillustrative embodiment of the invention, wherein:

The fi re is a vertical section throu h an oil dehydi ator illustratingthe improve construction wherein the electrode is kept 1nsulated fromthe shell.

Referring to the accompanying drawlng, wherein similar referencecharacters designate similar parts throu hout, the improved dehydratorcomprises a s ell 10having a con-- ical bottom 11 in which there is anoutlet 12 for water and other foreign matter. An inlet for oil, fromany'suitable source of supply, is indicated at 13 which supplies oil toan annular pipe 14 arranged on the interior of the shell. Ihis pipe hasa perforated bottom so that the oil flows downwardly therefrom betweenthej hell 10 and a skirt 15 suspended from the pipe in spaced relationto the shell. The roof or top of the shell is indicated at 16, throughwhich the electrode 17 extends. This electrode extends downwardly to apoint below the bottom of skirt 15 and it is intended that theelectrical discharge take lace between the electrode 17 and the wal s ofthe shell 10, causing the water particles to coalesce and dro out ofsuspension.

The electro e is surrounded by a bushing 18 of insulating material, suchas porcelain or the like. A shield 19 is secured to the roof 16 andextends downwardly about the bushing 18 in spaced relation thereto,forming a chamber 20. A valve controlled pipe 21 referabl communicateswith the interior 0 this cham er. As clearly shown upon the drawing, theshield 19 is frusto-conical in form, having a closed top and an openbottom. Also in the preferred form of construction the bushing 18preferably increases in cross sec tional area from bottom to top. Theoutlet for oil from the deh drator is indicated at 22 and a suitable oilevel indicator is indicated at 23.

The operation and advanta es of the improved construction are as f0 ows.Oil enters the dehydrator through pi e 13 and is subjected to theelectrical disc arge which causes the water articles to coalesce anddrop out of'the oil. h drator and passes out through outlet 23.

e chamber 20 confines an insulating fluid. The particular insulatinfluid is immaterial as natural gas, carbon ioxide, nitrogen, or anyother gas, may be used for this purpose. This as may be su plied to theinterior of cham er 20 throug pipe 21 and kept at sufiicient pressure tomaintain the level of oil within chamber 20 near the bottom of shield19. The-oil which enters the dehydrator is preferably preheated tomaintain the temperature within chamber 20 above the he oil then risesin the dedew point of the gas employed so that the gas will not condenseon the surface of the ushing 18 and possibly produce a short circuitbetween the electrode 17 and the roof of 5 the shell. As the shield 19is disposed wholly within the shell it is surrounded by an annulus ofoil having the highest temperature of the oil within the shell. Thishigh temperature oil surrounding the shield mamtains the temperature ofthe gas within the shield, or within chamber 20, at the sametemperature. Consequently there is no tendency for condensation to takeplace within chamber 20 on either the shield or on the bushing. By thusmaintaining an annulus of insulatin gas around the bushing 18 it will bereadily appreciated that no deposits will be formed on the exterior ofthe bushing 18 and it will be impossible for a short circuit to beformed between the electrode and the roof of the shell. The shell 19,while it might be cylindrical, is preferably frustoconical as shown, andlikewise the bushing 18 referably increases in cross sectional area roinbottom to top. This arrangement causes chamber 20 to decreasevolumetrically from bottom to to so that the level of oil in chamber 20will e kept relatively low although the pressure within the shell mayincrease fairly materially. In other words increases in pressure of oilwithin the shell will not be so readily perceptible by rises of li uidwithin the shield 19. It will be readi y appreciated, however, that thisadvantage is not essential and that a cylindrical shield could beemployed and likewise a bushing 18 which is of uniform size from top tobottom could be used.

It is not essential that a gas be used for an insulating fluid inchamber 20. Instead a dry oil or other liquid, having insulatingproperties, could be used. This could be introduced into chamber 20through pipe 21 or the entire shell could be completely filled with dryoil originally, the air being allowed to escape from chamber 20 throughpipe 21. Having thus been filled with dry oil, the flow of wet oilundergoing treatment within the dehydrator will not disturb it or carryit from within shield 19.

From the above described apparatus it will be appreciated that'a novelmeans and method is provided which will effectively maintain theelectrode 17 insulated from the shell so that no short circuits will beestablished between the electrode and the roof of the shell.

Various changes may be made in the de tails of construction withoutdepartin from the spirit or sco e of the invention as efined by theappends claims.

I-clarm: 1. An electrical'dehydrator for oil and the like comprising ashell, an electrode extending into the shell, a bushing ofinsulatingmaterial surroundin the shell, and a shield 1n the shell having a closedtop and an 0 en bottom surrounding the bushing, said shield serving toconfine an insulating gas about the bushing to prevent short circuitingbetween the electrode and the shield.

2. An electrical dehydrator for oil and the like comprisin a shell, anelectrode extending into the siell, a bushing of insulating materialsurrounding the electrode adjacent the shell, and a shield disposedwholly within the shell havin a closed top and an open bottomsurrounding the bushing, said shield serving to confine an insulatinggas about the bushin to preventshort circuiting betweenthe e ectrode andthe shield, said bushing hein characterized by increasing in crosssectional area from bottom to top.

3. An electrical dehydrator for oil and the like comprising a shell, anelectrode extending into the shell, a bushing insulating the electrodefrom the shell, and means providing an annular wall about the bushin inspaced relation to the bushing, said Will being disposed wholly withinthe shell, and serving to confine a gas about the bushing to preventshort circuitin 4. An electrical dehydrator for oil and the likecomprisin a shell, an electrode extending into the shell, a bushinginsulating the electrode from the shell means providin an annular wallabout the bushing in space relation to the bushing, said wall beingdisposed wholly within the shell, and serving to'confine a gas about thebushing to revent short circuiting, and a supply pipe or su plying thespace between the wall and t e bushing with gas.

In testimony whereof I have signed my name-t0 this specification.

R. T. HOVVES.

the electrode adjacent disposed wholly with-- DISOLAI MER1,891,645.Ray:-n0nd T. Howes, Los Angeles, Calif. METHOD OF INSULATINGHron VOLTAGES IN ELECTRICAL PRECIPITATORS. Patent dated December 20,1932. Disclaimer filed May 28, 1934, by the assignee, PetroleumRectifying Company of California.

Hereby enters this disclaimer in the said Raymond T. Howes patent tosaid claims 1, 2, 3, and 4 therein, reading as follows:

1. An electrical dehydrator for oil and the like corn rising a shell, anelectrode extending into the shell, a bushing of insulating materialsurrounding the electrode adjacent the shell, and a shield disposedwholly within the shell having a closed top and an open bottom.surrounding the bushing, said shield serving to confine an insulzliltingit; about the bushing to prevent short cirouiting between the electrodeand t e s e 2. An electrical dehydrator for oil and the like corn risinga shell, an electrode extending into the shell, a bushing of insulatingmateriaFsurrounding the electrode adjacent the shell, ands shielddisposed wholly within the shell having a closed top and an open bottomsurrounding the bushing, said shield serving to confine an insulatin gasabout the bushing to prevent short circuiting between the electrode andthe s 'eld, said bushing being characterized by in creasing in crosssection n1 area from bottom to top.

3. An electrical dehydrator for oil and the like comprising a shell, anelectrode extending into the shell, a b shing insulating the electrodefrom the shell, and means providing an annular well about the bushing inspaced relation to the bushing, said wall being disposed wholly withinthe shell, and serving to confine a gas about the bushing to preventshort circuiting.- 4. An electrical dehydrator for oil and the likecompnslng a shell, an electrode extending into the shell, a bushinginsulating the electrode from the shell, means providing an annular wellabout the bushing-1n spaced relation to the bushing, said wall beingdisposed wholly within the shell, and serving to confine a gas about thebushin to prevent short cirouiting, and a supply pipe for supplymg thespace between the wal and the bushing with gas.

[Ofiicial Gazette June 19. 1934.]

